RALEIGH — There is no doubt that cell phones are convenient for people on the go. However, there is one place they can be deadly, but people use them anyway.

Cell phones are so common that most people do not think twice about using them, butWakeMedis one place where they are not allowed.

It is no surprise that you must step outside to smoke a cigarette at a hospital, but you must also step outside to use a cell phone.

"The hospital uses all types of medical equipment in patient care. Any type of cell phone or radio transmits energy that could potentially interfere with the operation of that equipment," explained Gary Evans, director of Biomedical Engineering.

Much of the at-risk equipment involves patient monitors, including cardiac monitors that use a transmitter to send signals from the patient's bedside to a central monitoring system.

"It's using a radio wave, and it could be overpowered by another type of radio wave that could be a cell phone, a walkie-talkie or a similar device," said Evans.

Infusion pumps that regulate IV dosage and patients with pacemakers could also be affected.

"It's similar to the signs you see on microwave ovens where they warn people with pacemakers to stay a certain distance away from the microwave oven," said Evans.

That is why "cell phones prohibited" signs are up at hospitals. WakeMed officials admit the policy is just precautionary, but it is better to err on the side of caution when patients' lives are on the line.

If you happen to overlook the signs or forget the policy and use your cell phone, you can expect someone to politely come up to you and ask you to hang up.

As medical equipment gets more high-tech and lower-powered cell phones are introduced, in the next five or 10 years, this may not be a problem.

Cell phones, two-way radios and pagers that transmit can cause problems in hospitals, but the list of instruments affected is even longer.

Pacemakers, defibrillators, hearing aids, incubator heaters and ventilators can all be thrown off by electromagnetic signals.